Due to the frequent detection of sulfonamides and quinolones in surface water

trimethoprim (TMP) and enrofloxacin (EFX) were selected as target compounds to compare the degradation efficiency and kinetics of TMP and RFX in UV

UV/peroxymonosulfate (UV/PMS)

UV/persulfate (UV/PDS)

and UV/hydrogen peroxide (UV/H2O2) under different water matrix backgrounds. The quantum yields of TMP and EFX photodegradation were calculated at different pH values. Results show that the pseudo first-order rate constant k0 of TMP and EFX increased with the increase in pH

and the k0 of EFX photodegradation was significantly greater than that of TMP. At pH 3.0

7.0

and 11.0

the quantum yields of TMP and EFX photodegradation (λ=254 nm) were calculated as 0.001 0

0.001 3

0.003 6

and 0.005 3

0.051 1

0.064 5

respectively. The coupling of peroxides with UV increased the degradation rate of TMP and EFX

and an obvious enhancement was observed for TMP degradation

which had a small k0 of photodegradation. Under the background of ultrapure water

the k0 of TMP and EFX degradation by UV/PDS was the largest at pH 3.0 and 7.0

while the k0 of UV/PMS system was the largest at pH 11.0. In tap water

the degradation rates of TMP by UV/PMS and UV/PDS were close

which were greater than that of UV/H2O2 system

while for EFX degradation

the degradation efficiency of UV/PDS was the largest. In surface water

the efficiencies of TMP degradation by the three systems were close

among which UV/H2O2 was the best

while the degradation rate of UV/PDS for EFX was the highest.